AURORA, Colo. (AP) – Missy Franklin is starting to feel like a grown-up.

“I don’t know where the time went,” she said, breaking into a bubbly laugh. “We just went to the bank the other day and signed everything over. It’s crazy. I do feel a little bit older.”

Sure, the star of the London Olympics still has much of her life in front of her. But Franklin reached one important milestone last week, celebrating her 18th birthday, and she’ll mark another Monday when she graduates from her Denver-area high school.

“It’s been absolutely incredible, so much fun,” she told The Associated Press in a telephone interview. “It’s impossible to believe it’s almost over.”

Since returning from London, where she won four gold medals and five medals overall, Franklin has been able to meet everyone from Justin Bieber to Ben Affleck to Prince Harry — heady stuff, indeed. But she’s just as thrilled about being able to relish many of the normal activities of a senior at Regis Jesuit High School in Aurora.

Franklin led a retreat at the beginning of the school year (it’s kind of secretive, so don’t ask for details). She attended the winter formal, not to mention a couple of proms (one at her school, the other at her date’s school). She served as co-president of a club that organized various activities for the senior class, such as hot chocolate and cookies during a finals study breaks. She swam on the high school team, not surprisingly leading Jesuit to a state championship.

“We had so much fun,” Franklin said. “Everything was perfect. It was an incredible senior year.”

While most Olympians rightfully attempt to cash in on a triumph that comes only once every four years, there was never any doubt that Franklin would finish up high school after her remarkable performance in London. In fact, she said the thought of returning for her senior year at Regis was a big reason she did so well at the Olympics, becoming one of the breakout stars of the U.S. team with both her performance in the pool and exuberant personality.

Unlike so many young athletes, she didn’t want to miss anything along the way.

“I think it’s such a vital part of growing up, such a huge thing for me,” Franklin said. “My parents and I put so much emphasis on just staying normal. I wanted those experiences. I don’t want to look back 10 years from now wishing I had done my senior year of high school, wishing I had gone to my prom, wishing I had experienced those things. The people we meet, the experiences we go through, that’s what makes us the people we are, the people we are growing into. This is our time to make mistakes, to learn from them, to learn to shine. It’s such a beautiful time in your life.”

She’ll head to the University of California at Berkeley in the fall, still not ready to become a professional athlete. She plans to swim for her college team the next two years, finally turning pro after the 2015 NCAA championships, which will give her a chance to earn some of the big endorsement dollars leading into the Rio Olympics.

“If I do all four years of college, that would be the biggest financial mistake of my life,” she said. “As much as I would love to do four years, in terms of myself, my welfare, my family’s welfare, that wouldn’t be the smartest decision.”

Before college, there’s another bit of business to take care of this summer — the world championships in Barcelona.

For Franklin, the meet has special meaning because it will mark the end of her partnership with longtime coach Todd Schmitz. They want to go out with a bang before she leaves for college, where she’ll begin working with Cal coach Teri McKeever, who also headed the U.S. women’s team in London.

“We both really want to end it on a great note,” Franklin said. “It’s going to be really emotional, really sad. But I know we’ll maintain a great relationship through college. He’ll never be out of my life. It’s awesome to know that. But we’re ready to get back out there and show people that London wasn’t it, that I have a lot more offer.”

She expects to swim the same seven events she competed in at the Olympics — the 100- and 200-meter backstrokes, the 100 and 200 freestyles, along with all three relays — as well as a non-Olympic event, the 50 back.

If she wins them all, she would join Phelps as the only swimmers to win eight gold medals at a major swimming meet.

Just as impressive as Franklin’s swimming is how she’s handled her Olympic success. A couple of months ago, at a Grand Prix meet in Orlando, she remained on deck for nearly an hour after her last event, standing barefooted on a concrete floor, signing everything that was given to her for an autograph.

When Schmitz says she hasn’t changed a bit since London, it’s easy to believe.

“She doesn’t let things go to her head,” the coach said. “She’s very humble. She would never tell you how good she is. That’s the best thing about her. She always wants to get back in the pool the next day and get better.”

While Franklin dismisses any comparisons to the now-retired Phelps, fellow Olympian Jessica Hardy believes the teenager is the perfect swimmer to lead the U.S. program into a new era.

“She’s an amazing athlete,” Hardy said. “She also the best person I know. That makes it even better. It’s good for the sport of swimming, good for the American team, good for her.”

Besides the obvious physical talent — the 6-foot-1 height, the size-13 feet — Franklin seems to have that intangible that all the great ones have. While her persona on deck is much more laid back than the intensely focused Phelps, they both have the ability to perform their best in the biggest events.

“If she can do what she did at the Olympics, she can do anything,” Hardy marveled. “By Rio, she’ll be ready to kick butt.”

But Franklin will never forget that senior year at Regis.

“It’s really hard to put words to it,” she said. “It’s just been incredible.”